Free floating patient interface for laser surgery system

ABSTRACT

Systems and methods here may be used to support a laser eye surgery device, including a base assembly mounted to an optical scanning assembly via, a horizontal x axis bearing, a horizontal y axis bearing, and a vertical z axis bearing, mounted on the base assembly, configured to limit movement of the optical scanning assembly in an x axis, y axis and z axis respectively, relative to the base assembly, a vertical z axis spring, configured to counteract the forces of gravity on the optical scanning assembly in the z axis, and, mirrors mounted on the base assembly and positioned to reflect an energy beam into the optical scanning assembly no matter where the optical scanning assembly is located on the x axis bearing, the y axis bearing and the z axis bearing.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of priority as aContinuation-in-Part to U.S. application Ser. No. 14/190,827, titledFree Floating Patient Interface for Laser Surgery System, filed 26 Feb.2014 (which in turn claims the benefit of priority to U.S. provisionalapplication No. 61-780,881 filed on Mar. 13, 2013), as well as claimsthe benefit of priority as a Continuation-in-Part to U.S. applicationSer. No. 14/575,884, titled Laser Eye Surgery System, filed 18 Dec.2014, and issued as U.S. Pat. No. 9,849,033 on Dec. 26, 2017, whichclaims the benefit of priority to U.S. application Ser. No. 14/191,095,titled Laser Eye Surgery System, filed 26 Feb. 2014, and issued as U.S.Pat. No. 9,849,032 on Dec. 26 2017 (which in turn claims the benefit ofpriority to U.S. Provisional Application Ser. No. 61/780,736 filed onMar. 13, 2013), all of which applications are hereby incorporated byreference in their entirety.

BACKGROUND AND FIELD OF INVENTION

Laser eye surgery systems have become ubiquitous and varied in purpose.For example, a laser eye surgery system may be configured to reshape theanterior surface of the cornea via ablation to effect a refractivecorrection.

A laser eye surgery system may also be configured to create a cornealflap to expose an underlying portion of the cornea such that theunderlying portion can be reshaped via ablation and then recovered withthe flap. More recently-developed laser eye surgery systems may beconfigured to create one or more incisions in the cornea or limbus toreshape the cornea, create one or more incisions in the cornea toprovide access for a cataract surgical instrument and/or to provideaccess for implantation of an intraocular lens, incise a capsulotomy inthe anterior lens capsule to provide access for removal of a cataractouslens, segment a cataractous lens, and/or incise a capsulotomy in theposterior lens capsule opening.

Many laser eye surgery systems generate a series of laser beam pulsesvia a laser beam source. The laser beam pulses propagate along anoptical path to the patient's eye. The optical path typically includescontrollable elements such as scanning mechanisms and/or focusingmechanisms to control the direction and/or location of the emitted laserbeam pulses relative to the patient.

Some laser eye surgery systems are configured to track eye movement(e.g., change of viewing direction of the eye) such that control overthe direction and/or location of the emitted laser beam pulses can beaccomplished so as to account for the eye movement. For example, a lasereye surgery system may optically track a feature in the eye, such as anatural feature or a fiduciary marker added to the eye, so as to trackmovement of the eye.

In contrast, other laser eye surgery systems may be configured toinhibit eye movement. For example, a contact lens may be employed thatdirectly contacts the anterior surface of the cornea so as to restraineye movement. Such restraint, however, may cause associated patientdiscomfort and/or anxiety.

Beyond eye movement, many laser eye surgery systems are configured toinhibit relative movement between the patient and the laser eye surgerysystem. For example, a laser eye surgery system may include some sort ofsubstantial patient restraint feature such as a dedicated supportassembly (e.g., chair or bed), which can include restraint featuresconfigured to inhibit movement of the patient relative to the supportassembly. Such a dedicated support assembly may include a positioningmechanism by which the patient can be moved to suitably position thepatient's eye relative to the optical path of the laser eye surgerysystem. Additionally, a laser eye surgery system may be configured torigidly support components that determine the location of the opticalpath of the laser pulses so as to substantially prevent movement of theoptical path relative to the dedicated support assembly, thereby alsoinhibiting relative movement of the patient's eye relative to theemitted laser pulses. A dedicated support assembly and rigid support ofoptical path components, however, can add significant complexity andrelated cost to a laser eye surgery system. Additionally, the use ofrigid support of optical path components and a dedicated patient supportassembly can fail to preclude the possibility of some level ofsignificant relative movement between the patient and the laser eyesurgery system.

Thus, laser surgery systems with improved characteristics with respectto patient movement, and related methods, may be beneficial.

SUMMARY

Accordingly, to obviate one or more problems due to limitations anddisadvantages of the related art, this disclosure provides patientinterface assemblies and related methods that can be used in suitablelaser surgery systems such as, for example, laser eye surgery systems.In many embodiments, a patient interface assembly is configured toaccommodate relative movement of a patient while maintaining alignmentbetween a scanned electromagnetic treatment beam and the patient. Byaccommodating movement of the patient, additional system complexity andrelated cost associated with attempting to restrain movement of thepatient can be avoided. Additionally, accommodation of movement of thepatient can be employed to increase ease of use of a laser surgerysystem, such as by configuring the laser surgery system to be supportedby a repositionable cart that can be moved adjacent to an existingpatient support assembly (e.g., a non-dedicated patient support assemblysuch as a bed).

Thus, in one aspect, a method of accommodating patient movement in alaser surgery system is provided. The method includes using a firstsupport assembly to support a scanner so as to accommodate relativetranslation between the scanner and the first support assembly parallelto a first direction. The scanner is operable to controllably scan anelectromagnetic radiation beam and configured to be coupled with apatient so that the scanner moves in conjunction with movement of thepatient. A second support assembly is used to support the first supportassembly so as to accommodate relative translation between the firstsupport assembly and the second support assembly parallel to a seconddirection that is transverse to the first direction. A base assembly isused to support the second support assembly so as to accommodaterelative translation between the second support assembly and the baseassembly parallel to a third direction that is transverse to each of thefirst and second directions. The electromagnetic radiation beam ispropagated in a direction that is fixed relative to the base assembly.The first support assembly is used to support a first reflectorconfigured to reflect the electromagnetic radiation beam so as topropagate parallel to the first direction and to the scanner. The secondsupport assembly is used to support a second reflector configured toreflect the electromagnetic radiation beam so as to propagate parallelto the second direction and to be incident on the first reflector.Relative translation between the scanner and the first assembly, betweenthe first assembly and the second assembly, and between the secondassembly and the base assembly is used to accommodate three-dimensionalrelative translation between the scanner and the base assembly.

In many embodiments of the method, the scanner has particularoperational characteristics relative to the electromagnetic radiationbeam. For example, the scanner can be operable to scan theelectromagnetic radiation beam in at least two dimensions. The scannercan be operable to focus the electromagnetic radiation beam to a focalpoint. The scanner can be operable to scan the focal point in threedimensions.

In many embodiments of the method, the second direction is perpendicularto the first direction and the third direction is perpendicular to eachof the first and second directions. One of the first, second, and thirddirections can be vertically oriented. For example, the third directioncan be vertically oriented and each of the first and second directionscan be horizontally oriented. The method can include inhibiting at leastone of (1) gravity-induced movement of the scanner in the verticaldirection and (2) transfer of gravity-induced force to the patient.

In many embodiments of the method, the electromagnetic radiation beamincludes a series of laser pulses. The laser pulses can be configured tomodify eye tissue.

The method can include using the base assembly to support a thirdreflector. The third reflector can be configured to reflect theelectromagnetic radiation beam to propagate parallel to the thirddirection and to be incident on the second reflector.

The method can include monitoring one or more relative positions betweencomponents. For example, the method can include monitoring a relativeposition of at least one of the group consisting of (1) between thescanner and the first support assembly, (2) between the first supportassembly and the second support assembly, and (3) between the secondsupport assembly and the base assembly.

The method can include inhibiting relative movement during positioningof the scanner relative to the patient between at least one of (1) thescanner and the first support assembly, (2) the first support assemblyand the second support assembly, and (3) the second support assembly andthe base assembly. Such inhibiting relative movement during positioningof the scanner relative to the patient can be used to ensure thatadequate relative movement ranges are available after the scanner ispositioned relative to the patient.

In another aspect, a patient interface assembly for a laser eye surgerysystem is provided. The patient interface assembly includes an eyeinterface device, a scanner, a first support assembly, a second supportassembly, a base assembly, a beam source, a first reflector, and asecond reflector. The eye interface is configured to interface with aneye of a patient. The scanner is coupled with the eye interface andoperable to scan an electromagnetic radiation beam in at least twodimensions in an eye interfaced with the eye interface device. Thescanner and the eye interface move in conjunction with movement of theeye. The first support assembly supports the scanner so as toaccommodate relative translation between the scanner and the firstsupport assembly parallel to a first direction. The second supportassembly supports the first support assembly so as to accommodaterelative translation between the first support assembly and the secondsupport assembly parallel to a second direction that is transverse tothe first direction. The base assembly supports the second supportassembly so as to accommodate relative translation between the secondsupport assembly and the base assembly parallel to a third direction.The third direction is transverse to each of the first and seconddirections. The beam source generates the electromagnetic radiation beamand outputs the electromagnetic radiation beam so as to propagate in afixed direction relative to the base assembly. The first reflector issupported by the first support assembly and configured to reflect theelectromagnetic radiation beam to propagate parallel to the firstdirection and propagate to the scanner. The second reflector issupported by the second support assembly and configured to reflect theelectromagnetic radiation beam to propagate parallel to the seconddirection and to be incident on the first reflector. Relativetranslation between the scanner and the first assembly, between thefirst assembly and the second assembly, and between the second assemblyand the base assembly accommodates three-dimensional relativetranslation between the eye interface and the base assembly.

The patient interface assembly can include an objective lens assemblydisposed between the scanner and the eye interface. For example, theelectromagnetic radiation beam can propagate from the scanner to passthrough the objective lens assembly and then from the objective lensassembly through the eye interface.

In many embodiments of the patient interface assembly, theelectromagnetic radiation beam is focused to a focal point. The scannercan be operable to scan the focal point in three dimensions in an eyeinterfaced with the eye interface device.

In many embodiments of the patient interface assembly, the scannerincludes a z-scan device and an xy-scan device. The z-scan device can beoperable to change a depth of the focal point in the eye. The xy-scandevice can be operable to scan the focal point in two dimensionstransverse to the propagation direction of the electromagnetic radiationbeam.

In many embodiments of the patient interface assembly, the seconddirection is perpendicular to the first direction and the thirddirection is perpendicular to each of the first and second directions.One of the first, second, and third directions can be verticallyoriented. The patient interface assembly can include a counter-balancemechanism coupled with the scanner and configured to inhibit at leastone of (1) gravity-induced movement of the eye interface in the verticaldirection and (2) transfer of gravity-induced force to an eye coupledwith the eye interface device. The third direction can be verticallyoriented and each of the first and second directions can be horizontallyoriented.

The patient interface assembly can include at least one sensor tomonitor relative position between components of the patient interfaceassembly. For example, the patient interface assembly can include atleast one sensor configured to monitor relative position of at least oneof the group consisting of between the scanner and the first supportassembly, between the first support assembly and the second supportassembly, and between the second support assembly and the base assembly.

In many embodiments of the patient interface assembly, theelectromagnetic radiation beam includes a series of laser pulses. Thelaser pulses can be configured to modify eye tissue.

The patient interface assembly can include at least one device (e.g.,one or more solenoid brake assemblies, one or more detent mechanisms, orany other suitable mechanism configured to selectively inhibit relativemovement between components coupled for relative movement) configured toinhibit relative movement during positioning of the scanner relative tothe patient between at least one of (1) the scanner and the firstsupport assembly, (2) the first support assembly and the second supportassembly, and (3) the second support assembly and the base assembly.Such a device(s) can be used to ensure that adequate relative movementranges are available after the scanner is positioned relative to thepatient.

In many embodiments, the patient interface assembly includes a thirdreflector supported by the base assembly. The third reflector isconfigured to reflect the electromagnetic radiation beam to propagateparallel to the third direction and to be incident on the secondreflector.

In another aspect, a method of accommodating patient movement in a lasersurgery system is provided. The method includes using a using a firstsupport assembly to support a scanner so as to accommodate relativemovement between the scanner and the first support assembly so as toaccommodate patient movement. The scanner is operable to controllablyscan an electromagnetic radiation beam and configured to be coupled witha patient so that the scanner moves in conjunction with movement of thepatient. The method further includes using a beam source to generate theelectromagnetic radiation beam. The method further includes propagatingthe electromagnetic radiation beam from the beam source to the scanneralong an optical path having an optical path length that changes inresponse to patient movement.

The method can include further acts related to the optical path. Forexample, the method can include using a second support assembly tosupport the first support assembly so as to accommodate relativemovement between the first support assembly and the second supportassembly so as to accommodate patient movement. The method can includeusing the first support assembly to support a first reflector configuredto reflect the electromagnetic radiation beam so as to propagate to thescanner along a portion of the optical path. The method can includeusing a base assembly to support the second support assembly so as toaccommodate relative movement between the second support assembly andthe base assembly so as to accommodate patient movement. The method caninclude using the second support assembly to support a second reflectorconfigured to reflect the electromagnetic radiation beam to propagatealong a portion of the optical path so as to be incident on the firstreflector. The method can include using the base assembly to support athird reflector configured to reflect the electromagnetic radiation beamto propagate along a portion of the optical path so as to be incident onthe second reflector.

The method can include the use of relative translation and/or relativerotation between optical path related components. For example, therelative movement between the scanner and the first support assembly canbe a translation in a first direction. The relative movement between thefirst support assembly and the second support assembly can be atranslation in a second direction that is transverse to the firstdirection. The relative movement between the second support assembly andthe base assembly can be a translation in a third direction that istransverse to each of the first and second directions. The seconddirection can be perpendicular to the first direction. The thirddirection can be perpendicular to each of the first and seconddirections. At least one of (1) the relative movement between thescanner and the first support assembly, (2) the relative movementbetween the first support assembly and the second support assembly, and(3) the relative movement between the second support assembly and thebase assembly can be a relative rotation.

The method can include inhibiting at least one of (1) gravity-inducedmovement of the scanner in the vertical direction and (2) transfer ofgravity-induced force to the patient. One of the first, second, andthird directions can be vertically oriented. For example, the thirddirection can be vertically oriented and each of the first and seconddirections can be horizontally oriented.

The scanner can be operable to scan any suitable electromagneticradiation beam in any suitable fashion. For example, the scanner can beoperable to scan the electromagnetic radiation beam in at least twodimensions. The scanner can be operable to focus the electromagneticradiation beam to a focal point and scan the focal point in threedimensions. The scanner can be configured to be coupled with an eye ofthe patient and to controllably scan a focal point of theelectromagnetic radiation beam within a tissue of the eye. Theelectromagnetic radiation beam can include a series of laser pulsesconfigured to modify eye tissue.

The method can include monitoring relative position and/or relativeorientation between optical path related components. For example, themethod can include monitoring at least one of a relative position and arelative orientation of at least one of the group consisting of (1)between the scanner and the first support assembly, (2) between thefirst support assembly and the second support assembly, and (3) betweenthe second support assembly and the base assembly.

The method can include inhibiting relative movement between optical pathrelated components during positioning of the scanner relative to thepatient. For example, the method can include inhibiting relativemovement during positioning of the scanner relative to the patientbetween at least one of (1) the scanner and the first support assembly,(2) the first support assembly and the second support assembly, and (3)the second support assembly and the base assembly.

In another aspect, a patient interface assembly for a laser eye surgerysystem is provided. The patient interface assembly includes an eyeinterface device, a scanner, a first support assembly, and beam source.The eye interface device is configured to interface with an eye of apatient. The scanner is configured to be coupled with the eye interfacedevice and operable to scan an electromagnetic radiation beam in atleast two dimensions in an eye interfaced with the eye interface device.The scanner and the eye interface device move in conjunction withmovement of the eye. The first support assembly supports the scanner soas to accommodate relative movement between the scanner and the firstsupport assembly parallel so as to accommodate movement of the eye. Thebeam source generates the electromagnetic radiation beam. Theelectromagnetic radiation beam propagates from the beam source to thescanner along an optical path having an optical path length that variesin response to movement of the eye.

The patient interface assembly can include additional optical pathrelated components. For example, the patient interface assembly caninclude a second support assembly that supports the first supportassembly so as to accommodate relative movement between the firstsupport assembly and the second support assembly so as to accommodatemovement of the eye. The patient interface assembly can include a firstreflector supported by the first support assembly and configured toreflect the electromagnetic radiation beam to propagate to the scanneralong a portion of the optical path. The patient interface assembly caninclude a base assembly that supports the second support assembly so asto accommodate relative movement between the second support assembly andthe base assembly so as to accommodate movement of the eye. The patientinterface assembly can include a second reflector supported by thesecond support assembly and configured to reflect the electromagneticradiation beam to propagate along a portion of the optical path so as tobe incident on the first reflector. The patient interface assembly caninclude a third reflector supported by the base assembly and configuredto reflect the electromagnetic radiation beam to propagate along aportion of the optical path so as to be incident on the secondreflector.

The patient interface assembly can employ relative translation and/orrelative rotation between optical path related components. For example,the relative movement between the scanner and the first support assemblycan be a translation in a first direction. The relative movement betweenthe first support assembly and the second support assembly can be atranslation in a second direction that is transverse to the firstdirection. The relative movement between the second support assembly andthe base assembly can be a translation in a third direction that istransverse to each of the first and second directions. The seconddirection can be perpendicular to the first direction. The thirddirection can be perpendicular to each of the first and seconddirections. At least one of (1) the relative movement between thescanner and the first support assembly, (2) the relative movementbetween the first support assembly and the second support assembly, and(3) the relative movement between the second support assembly and thebase assembly can be a relative rotation.

The patient interface assembly can include a counter-balance mechanismconfigured to inhibit at least one of (1) gravity-induced movement ofthe scanner in the vertical direction and (2) transfer ofgravity-induced force to eye of the patient. The third direction can bevertically oriented and each of the first and second directions can behorizontally oriented.

The scanner of the patient interface assembly can be operable to scanany suitable electromagnetic radiation beam in any suitable fashion. Forexample, the scanner can be operable to scan the electromagneticradiation beam in at least two dimensions. The scanner can be operableto focus the electromagnetic radiation beam to a focal point and scanthe focal point in three dimensions. The scanner can be configured to becoupled with an eye of the patient and to controllably scan a focalpoint of the electromagnetic radiation beam within a tissue of the eye.The electromagnetic radiation beam can include a series of laser pulsesconfigured to modify eye tissue. The scanner can include a z-scan deviceand an xy-scan device. The z-scan device can be operable to change adepth of the focal point in the eye. The xy-scan device can be operableto scan the focal point in two dimensions transverse to the propagationdirection of the electromagnetic radiation beam.

The patient interface assembly can include other suitable optical pathrelated components. For example, the patient interface assembly caninclude at least one sensor configured to monitor relative position ofat least one of the group consisting of (1) between the scanner and thefirst support assembly, (2) between the first support assembly and thesecond support assembly, and (3) between the second support assembly andthe base assembly. The patient interface assembly can include anobjective lens assembly disposed between and coupled with the scannerand the eye interface device. The electromagnetic radiation beam canpropagate from the scanner to pass through the objective lens assemblyand then from the objective lens assembly through the eye interfacedevice. The patient interface assembly can include at least one device(e.g., one or more solenoid brake assemblies, one or more detentmechanisms, or any other suitable mechanism configured to selectivelyinhibit relative movement between components coupled for relativemovement) configured to inhibit relative movement during positioning ofthe scanner relative to the patient between at least one of (1) thescanner and the first support assembly, (2) the first support assemblyand the second support assembly, and (3) the second support assembly andthe base assembly. Such a device(s) can be used to ensure that adequaterelative movement ranges are available after the scanner is positionedrelative to the patient.

For a fuller understanding of the nature and advantages of the presentinvention, reference should be made to the ensuing detailed descriptionand accompanying drawings. Other aspects, objects and advantages of theinvention will be apparent from the drawings and detailed descriptionthat follows.

This summary and the following detailed description are merelyexemplary, illustrative, and explanatory, and are not intended to limit,but to provide further explanation of the invention as claimed.Additional features and advantages of the invention will be set forth inthe descriptions that follow, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription, claims and the appended drawings.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference in their entirety tothe same extent as if each individual publication, patent, or patentapplication was specifically and individually indicated to beincorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is a schematic diagram of a laser surgery system, in accordancewith many embodiments, in which a patient interface device is coupled toa laser assembly by way of a scanner and free-floating mechanism thatsupports the scanner.

FIG. 2 shows an isometric view of a patient interface assembly, inaccordance with many embodiments, that includes a scanner supported by afree-floating mechanism.

FIG. 3 is a simplified block diagram of acts of a method, in accordancewith many embodiments, for accommodating patient movement in a lasersurgery system.

FIG. 4 is a simplified block diagram of optional acts, in accordancewith many embodiments, that can be accomplished in the method of FIG. 3.

FIG. 5 schematically illustrates relative movements that can be used ina patient interface assembly, in accordance with many embodiments, thatincludes a scanner supported by a free-floating mechanism.

FIG. 6A is a simplified block diagram of acts of another method, inaccordance with many embodiments, for accommodating patient movement ina laser surgery system.

FIG. 6B is a simplified block diagram of optional acts, in accordancewith many embodiments, that can be accomplished in the method of FIG.6A.

FIG. 7 is a schematic diagram of a laser surgery system, in accordancewith many embodiments, in which an eye interface device is coupled to alaser assembly by way of a scanner and free-floating mechanism thatsupports the scanner.

FIG. 8 is a schematic diagram of another laser surgery system, inaccordance with many embodiments, in which an eye interface device iscoupled to a laser assembly by way of a scanner and free-floatingmechanism that supports the scanner.

FIG. 9 is another schematic diagram of the laser surgery system, inaccordance with many embodiments, in which an eye interface device iscoupled to a laser assembly by way of a scanner and free-floatingmechanism that supports the scanner.

DETAILED DESCRIPTION

In the following description, various embodiments of the presentinvention will be described. For purposes of explanation, specificconfigurations and details are set forth in order to provide a thoroughunderstanding of the embodiments. It will also, however, be apparent toone skilled in the art that the present invention may be practicedwithout the specific details. Furthermore, well-known features may beomitted or simplified in order not to obscure the embodiment beingdescribed.

The drawings and related descriptions of the embodiments have beensimplified to illustrate elements that are relevant for a clearunderstanding of these embodiments, while eliminating various otherelements found in conventional laser eye surgery systems. Those ofordinary skill in the art may thus recognize that other elements and/orsteps are desirable and/or required in implementing the embodiments thatare claimed and described. But, because those other elements and stepsare well-known in the art, and because they do not necessarilyfacilitate a better understanding of the embodiments, they are notdiscussed. This disclosure is directed to all applicable variations,modifications, changes, and implementations known to those skilled inthe art. As such, the following detailed descriptions are merelyillustrative and exemplary in nature and are not intended to limit theembodiments of the subject matter or the uses of such embodiments. Asused in this application, the terms “exemplary” and “illustrative” mean“serving as an example, instance, or illustration.” Any implementationdescribed as exemplary or illustrative is not meant to be construed aspreferred or advantageous over other implementations. Further, there isno intention to be bound by any expressed or implied theory presented inthe preceding background, brief summary, or the following detaileddescription.

Patient interface assemblies and related methods for use in lasersurgery systems are provided. While described herein as used in lasereye surgery systems, the patient interface assemblies and methodsdescribed herein can be used in any other suitable laser surgery system.In many embodiments, a free-floating patient interface assembly isconfigured to accommodate movement of a patient relative to the lasersurgery system while maintaining alignment between an electromagnetictreatment beam emitted by the laser surgery system and the patient.

Referring now to the drawings in which like numbers reference similarelements, FIG. 1 schematically illustrates a laser surgery system 10, inaccordance with many embodiments. The laser surgery system 10 includes alaser assembly 12, a free-floating mechanism 14, a scanning assembly 16,an objective lens assembly 18, and a patient interface device 20. Thepatient interface device 20 is configured to interface with a patient22. The patient interface device 20 is supported by the objective lensassembly 18. The objective lens assembly 18 is supported by the scanningassembly 16. The scanning assembly 16 is supported by the free-floatingmechanism 14. The free-floating mechanism 14 has a portion having afixed position and orientation relative to the laser assembly 12.

In many embodiments, the patient interface device 20 is configured tointerface with an eye of the patient 22. For example, the patientinterface device 20 can be configured to be vacuum coupled to an eye ofthe patient 22 such as described in U.S. Publication No. US 2014-0128821A1 (U.S. patent application Ser. No. 14/068,994, entitled “LiquidOptical Interface for Laser Eye Surgery System”, filed Oct. 31, 2013).The laser surgery system 10 can further optionally include a baseassembly 24 that can be fixed in place or repositionable. For example,the base assembly 24 can be supported by a support linkage that isconfigured to allow selective repositioning of the base assembly 24relative to a patient and secure the base assembly 24 in a selectedfixed position relative to the patient. Such a support linkage can besupported in any suitable manner such as, for example, by a fixedsupport base or by a movable cart that can be repositioned to a suitablelocation adjacent to a patient. In many embodiments, the support linkageincludes setup joints with each setup joint being configured to permitselective articulation of the setup joint and can be selectively lockedto prevent inadvertent articulation of the setup joint, thereby securingthe base assembly 24 in a selected fixed position relative to thepatient when the setup joints are locked.

Eye Interface Examples

Certain older methods to measure the force on the eye 22 of the patientinterface device 20 utilized three load cells. The slow response time(approx. ½ sec.) made this less than effective for docking the patientto the system and monitoring the force during the procedure. Plus, theload cells were used both to precisely locate the patient interface andmeasure the force on the patient's eye. Hence the load cells weremounted in a statically indeterminate manner and as a result hysteresiswas a problem. These flaws made the load cell assembly unsuitable as amonitor for patient safety.

In many embodiments, the force sensor here uses a microelectromechanicalsystem (MEMS) device. It utilizes the piezo resistive properties of thesilicon device to convert the applied load into an electrical signal inthe range of tens of millivolts. By preloading the force sensor incompression, the force sensor assembly can measure an appropriate rangeof axial and lateral forces exerted on the patient's eye. This forcesensor assembly separates the functions of load sensing and preciselylocating the patient so that hysteresis is not an issue. The responsetime is on the order of tens of microseconds and can be used toaccurately measure and monitor the forces on a patient's eye whiledocking and during the procedure. As an added benefit, the force sensorsare packaged in low profile Surface Mount Technology (SMT) package sothat the force sensor assembly is thinner than the original load cellassembly by approximately 8 mm, improving the clearance between thesystem and the patient. The force sensor assembly has been designed tolimit the load that can be applied to the force sensor effectivelypreventing an overload condition from ever occurring.

Laser Assembly Examples

In many embodiments, the laser assembly 12 is configured to emit anelectromagnetic radiation beam 26. The beam 26 can include a series oflaser pulses of any suitable energy level, duration, and repetitionrate.

In many embodiments, the laser assembly 12 incorporates femtosecond (FS)laser technology. By using femtosecond laser technology, a shortduration (e.g., approximately 10⁻¹³ seconds in duration) laser pulse(with energy level in the micro joule range) can be delivered to atightly focused point to disrupt tissue, thereby substantially loweringthe energy level required as compared to laser pulses having longerdurations.

The laser assembly 12 can produce laser pulses having a wavelengthsuitable to treat and/or image tissue. For example, the laser assembly12 can be configured to emit an electromagnetic radiation beam 26 suchas emitted by any of the laser surgery systems described in U.S.Publication Nos. US 2014-0163534 A1 and US 2011-0172649 A1 (co-pendingU.S. patent application Ser. No. 14/069,042, entitled “Laser Eye SurgerySystem”, filed Oct. 31, 2013; U.S. patent application Ser. No.12,987,069, entitled “Method and System For Modifying Eye Tissue andIntraocular Lenses”, filed Jan. 7, 2011). For example, the laserassembly 12 can produce laser pulses having a wavelength from 1020 nm to1050 nm. For example, the laser assembly 12 can have a diode-pumpedsolid-state configuration with a 1030 (±5) nm center wavelength. Asanother example, the laser assembly 12 can produce laser pulses having awavelength 320 nm to 430 nm. For example, the laser assembly 12 caninclude an Nd:YAG laser source operating at the 3rd harmonic wavelength,355 nm. The laser assembly 12 can also include two or more lasers of anysuitable configuration.

The laser assembly 12 can include control and conditioning components.For example, such control components can include components such as abeam attenuator to control the energy of the laser pulse and the averagepower of the pulse train, a fixed aperture to control thecross-sectional spatial extent of the beam containing the laser pulses,one or more power monitors to monitor the flux and repetition rate ofthe beam train and therefore the energy of the laser pulses, and ashutter to allow/block transmission of the laser pulses. Suchconditioning components can include an adjustable zoom assembly and afixed optical relay to transfer the laser pulses over a distance whileaccommodating laser pulse beam positional and/or directionalvariability, thereby providing increased tolerance for componentvariation.

In many embodiments, the laser assembly 12 has a fixed position relativeto the base assembly 24. The beam 26 emitted by the laser assembly 12propagates along a fixed optical path to the free-floating mechanism 14.The beam 12 propagates through the free-floating mechanism 14 along avariable optical path 28, which delivers the beam 26 to the scanningassembly 16. In many embodiments, the beam 26 emitted by the laserassembly 12 is collimated so that the beam 26 is not impacted by patientmovement induced changes in the length of the optical path between thelaser assembly 12 and the scanning assembly 16. The scanning assembly 16is operable to scan the beam 26 (e.g., via controlled variabledeflection of the beam 26) in at least one dimension. In manyembodiments, the scanner is operable to scan the beam in two dimensionstransverse to the direction of propagation of the beam 26 and is furtheroperable to scan the location of a focal point of the beam 26 in thedirection of propagation of the beam 26. The scanned beam is emittedfrom the scanning assembly 16 to propagate through the objective lensassembly 18, through the interface device 20, and to the patient 22.

The free-floating mechanism 14 is configured to accommodate a range ofmovement of the patient 22 relative to the laser assembly 12 in one ormore directions while maintaining alignment of the beam 24 emitted bythe scanning assembly 16 with the patient 22. For example, in manyembodiments, the free-floating mechanism 14 is configured to accommodatea range movement of the patient 22 in any direction defined by anycombination of unit orthogonal directions (X, Y, and Z).

The free-floating mechanism 14 supports the scanning assembly 16 andprovides the variable optical path 28, which changes in response tomovement of the patient 22. Because the patient interface device 20 isinterfaced with the patient 22, movement of the patient 22 results incorresponding movement of the patient interface device 20, the objectivelens assembly 18, and the scanning assembly 16. The free-floatingmechanism 14 can include, for example, any suitable combination of alinkage that accommodates relative movement between the scanningassembly 16 and the laser assembly 12 and optical components suitablytied to the linkage so as to form the variable optical path 28.

FIG. 2 shows an free floating assembly 16 to illustrate an exampleembodiment of a suitable combination of a linkage that accommodatesrelative movement between the scanning assembly 16 and the laserassembly 12 and optical components suitably tied to the linkage so as toform the variable optical path 28. The free floating assembly 16includes an eye interface device 20, the objective lens assembly 18, thescanning assembly 16, and the free-floating mechanism 14. Thefree-floating mechanism 14 includes a first support assembly 32, asecond support assembly 34, and a base assembly 36. The eye interfacedevice 20 is coupled with and supported by the objective lens assembly18. The objective lens assembly 18 is coupled with and supported by thescanning assembly 16. The combination of the interface device 20, theobjective lens assembly 18, and the scanning assembly 16 form a unitthat moves in unison in conjunction with movement of the patient.

The first support assembly 32 includes a first end frame 38, a secondend frame 40, and transverse rods 42, 44, which extend between andcouple to the end frames 38, 40. The transverse rods 42, 44 are orientedparallel to a first direction 46. The scanning assembly 16 is supportedby the transverse rods 42, 44 and slides along the rods 42, 44 inresponse to patient movement parallel to the first direction 46. Thetransverse rods 42, 44 form part of a linear bearing accommodatingpatient movement parallel to the first direction 46.

The second support assembly 34 includes a first end frame 48, anintermediate frame 50, transverse rods 52, 54, a second end frame 56,and vertical rods 58, 60. The transverse rods 52, 54 extend between andcouple to the first end frame 48 and to the intermediate frame 50. Thetransverse rods 52, 54 are oriented parallel to a second direction 62,which is at least transverse to and can be orthogonal to the firstdirection 46. Each of the first and second directions 46, 62 can behorizontal. The first support assembly 32 is supported by the transverserods 52, 54 and slides along the rods 52, 54 in response to patientmovement parallel to the second direction 62. The transverse rods 52, 54form part of a linear bearing accommodating patient movement parallel tothe second direction 62. The vertical rods 58, 60 extend between andcouple to the intermediate frame 50 and to the second end frame 56. Thevertical rods 58, 60 are oriented parallel to a third direction 64,which is at least transverse to each of first and second directions 46,62, and can be orthogonal to at least one of the first and seconddirections 46, 62. The vertical rods 58, 60 form part of a linearbearing accommodating relative movement between the second supportassembly 34 and the base assembly 36 parallel to the third direction 64,thereby accommodating patient movement parallel to the third direction64.

First, second, and third reflectors 66, 68, 70 (e.g., mirrors) aresupported by the free-floating mechanism 14 and configured to reflectthe electromagnetic radiation beam 26 to propagate along a variableoptical path 28. The first reflector 66 is mounted to the first supportassembly 32 (to second end frame 42 in the illustrated embodiment). Thesecond reflector 68 is mounted to the second support assembly 34 (tointermediate frame 50 in the illustrated embodiment). The thirdreflector 70 is mounted to the base assembly 36. In operation, the beam26 emitted by the laser assembly is deflected by the third reflector 70so as to propagate parallel to the third direction 64 and be incidentupon the second reflector 68. The second reflector 68 deflects the beam26 so as to propagate parallel to the second direction 62 and beincident upon the first reflector 66. The first reflector 66 deflectsthe beam 26 so as to propagate parallel to the first direction 46 andinto the scanning assembly 16, which then controllably scans and outputsthe scanned beam through the objective lens assembly 18 and the eyeinterface device 20. By propagating the beam 26 parallel to the thirddirection 64 from the third reflector 70 to the second reflector 68, thelength of the corresponding portion of the variable optical path 28 canbe varied so as to accommodate relative movement of the patient relativeto the third direction 64. By propagating the beam 26 parallel to thesecond direction 62 from the second reflector 68 to the first reflector66, the length of the corresponding portion of the variable optical path28 can be varied so as to accommodate relative movement of the patientrelative to the second direction 62. By propagating the beam 26 parallelto the first direction 46 from the first reflector 66 to the scanningassembly 16, the length of the corresponding portion of the variableoptical path 28 can be varied so as to accommodate relative movement ofthe patient relative to the first direction 46.

In the illustrated embodiment, the free-floating mechanism 14 furtherincludes a first solenoid brake assembly 72, a second solenoid brakeassembly 74, and a third solenoid brake assembly 76. The solenoid brakeassemblies 72, 74, 76 are operable to selectively prevent inadvertentarticulation of the free-floating mechanism 14 during initialpositioning of the scanning assembly 16 relative to a patient's eye. Forexample, in the absence of any mechanism for preventing inadvertentarticulation of the free-floating mechanism 14, movement of the scanningassembly 16 may induce inadvertent articulation of the free-floatingmechanism 14, especially when a user induces movement of the scanningassembly 16 through contact with, for example, the objective lensassembly 18 to move the objective lens assembly 18 into a suitablelocation relative to the patient. When the laser surgery system 10 issupported by a support linkage mechanism that includes setup joints,preventing inadvertent articulation of the free-floating mechanism 14can be used to ensure that the initial positioning of the laser surgerysystem 10 occurs via articulation of the setup joints instead of viaarticulation of the free-floating mechanism 14.

The first solenoid brake assembly 72 is configured to selectivelyprevent inadvertent movement between the scanning assembly 16 and thefirst support assembly 32. Engagement of the first solenoid brakeassembly 72 prevents movement of the scanning assembly 16 along thetransverse rods 42, 44, thereby preventing relative movement between thescanning assembly 16 and the first support assembly 32 parallel to thefirst direction 46. When the first solenoid brake assembly 72 is notengaged, the scanning assembly 16 is free to slide along the transverserods 42, 44, thereby permitting relative movement between the scanningassembly 16 and the first support assembly 32 parallel to the firstdirection 46. In many embodiments, the free-floating mechanism 14includes a detent mechanism and/or an indicator that is configured topermit engagement of the first solenoid brake assembly 72 when thescanning assembly 16 is centered relative to its range of travel alongthe transverse rods 42, 44, thereby ensuring equal range of travel ofthe scanning assembly 16 in both directions parallel to the firstdirection 46 when the first solenoid brake assembly 72 is disengagedfollowing positioning of the objective lens assembly 18 relative to thepatient.

The second solenoid brake assembly 74 is configured to selectivelyprevent inadvertent movement between the first support assembly 32 andthe second support assembly 34. Engagement of the second solenoid brakeassembly 74 prevents movement of the first support assembly 32 along thetransverse rods 52, 54, thereby preventing relative movement between thefirst support assembly 32 and the second support assembly 34 parallel tothe second direction 62. When the second solenoid brake assembly 74 isnot engaged, the first support assembly 32 is free to slide along thetransverse rods 52, 54, thereby permitting relative movement between thefirst support assembly 32 and the second support assembly 34 parallel tothe second direction 62. In many embodiments, the free-floatingmechanism 14 includes a detent mechanism and/or an indicator that isconfigured to permit engagement of the second solenoid brake assembly 74when the first support assembly 32 is centered relative to its range oftravel along the transverse rods 52, 54, thereby ensuring equal range oftravel of the first support assembly 32 in both directions parallel tothe second direction 62 when the second solenoid brake assembly 74 isdisengaged following positioning of the objective lens assembly 18relative to the patient.

The third solenoid brake assembly 76 is configured to selectivelyprevent inadvertent movement between the second support assembly 34 andthe base assembly 36. Engagement of the third solenoid brake assembly 76prevents movement of the base assembly 36 along the vertical rods 58,60, thereby preventing relative movement between the second supportassembly 34 and the base assembly 36 parallel to the third direction 64.When the third solenoid brake assembly 76 is not engaged, the baseassembly 36 is free to slide along the vertical rods 58, 60, therebypermitting relative movement between the second support assembly 34 andthe base assembly 36 parallel to the third direction 64. In manyembodiments, the free-floating mechanism 14 includes a detent mechanismand/or an indicator that is configured to permit engagement of the thirdsolenoid brake assembly 76 when the base assembly 36 is centeredrelative to its range of travel along the vertical rods 58, 60, therebyensuring equal range of travel of the base assembly 36 in bothdirections parallel to the third direction 64 when the third solenoidbrake assembly 76 is disengaged following positioning of the objectivelens assembly 18 relative to the patient.

In an optional embodiment, the third reflector 70 is omitted and theincoming beam 26 is directed to propagate parallel to the thirddirection 64 and be incident on the second reflector 68. Each of thereflectors 66, 68, 70 can be adjustable in position and/or inorientation and thereby can be adjusted to align the correspondingportions of the variable optical path 28 with the first, second, andthird directions 46, 62, and 64, respectively. Accordingly, the use ofthe third reflector 70 can provide the ability to align the portion ofthe variable optical path 28 between the third reflector 70 and thesecond reflector 68 so as to be parallel to the third direction 64 andthereby compensate for relative positional and/or orientationvariability between the laser assembly 12 and the free-floatingmechanism 14.

In the illustrated embodiment of the free floating assembly 16, thefirst and second directions 46, 62 can be horizontal and the thirddirection 64 can be vertical. The free-floating mechanism 14 can alsoinclude a counter-balance mechanism coupled with the scanner andconfigured to inhibit gravity-induced movement of the eye interfacedevice 20 and/or inhibit the transfer of gravity-induced forces from theeye interface device 20 to an eye coupled with the eye interface device20. For example, a counter-balance mechanism can be employed to apply acounter-balancing vertical force to the second assembly 34, therebyinhibiting or even preventing gravity-induced relative movement betweenthe second assembly 34 and the base assembly 36 and/or inhibiting thetransfer of gravity-induced forces from the eye interface device 20 toan eye coupled with the eye interface device 20.

Other suitable variations of the free floating assembly 16 are possible.For example, the scanning assembly 16 can be slidably supported relativeto a first support assembly via a vertically-oriented linear bearing.The first support assembly can be slidably supported relative to asecond support assembly via a first horizontally-oriented linearbearing. The second support assembly can be slidably supported relativeto a base assembly via a second horizontally-oriented linear bearingthat is oriented transverse (e.g., perpendicular) to the firsthorizontally-oriented linear bearing. In such a configuration, acounter-balancing mechanism can be used to apply a counter-balancingforce to the scanning assembly 16, thereby inhibiting or even preventinggravity-induced relative movement of the scanning assembly 16 and theeye interface device 20 and/or inhibiting or even preventing thetransfer of gravity-induced force from the eye interface device 20 to aneye coupled with the eye interface device 20. The free floating assembly16 can also incorporate one or more sensors configured to monitorrelative position 1) between the scanning assembly 16 and the firstsupport assembly 32, 2) between the first support assembly 32 and thesecond support assembly 34, and/or 3) between the second supportassembly 34 and the base assembly 36.

FIG. 3 is a simplified block diagram of acts of a method 100, inaccordance with many embodiments, of accommodating patient movement in alaser surgery system. Any suitable device, assembly, and/or systemdescribed herein can be used to practice the method 100. The method 100includes using a first support assembly (e.g., first support assembly32) to support a scanner (e.g., scanning assembly 16) so as toaccommodate relative translation between the scanner and the firstsupport assembly parallel to a first direction (e.g., direction 46). Thescanner is operable to controllably scan an electromagnetic radiationbeam (e.g., beam 26) and configured to be coupled with a patient so thatthe scanner moves in conjunction with movement of the patient (act 102).A second support assembly (e.g., second support assembly 34) is used tosupport the first support assembly so as to accommodate relativetranslation between the first support assembly and the second supportassembly parallel to a second direction (e.g., direction 62) that istransverse to the first direction (act 104). A base assembly (e.g., baseassembly 36) is used to support the second support assembly so as toaccommodate relative translation between the second support assembly andthe base assembly parallel to a third direction (e.g., direction 64)that is transverse to each of the first and second directions (act 106).The electromagnetic radiation beam is propagated in a direction that isfixed relative to the base assembly (act 108). The first supportassembly is used to support a first reflector (e.g., first reflector 66)configured to reflect the electromagnetic radiation beam so as topropagate parallel to the first direction and to the scanner (act 110).The second support assembly is used to support a second reflector (e.g.,second reflector 68) configured to reflect the electromagnetic radiationbeam so as to propagate parallel to the second direction and to beincident on the first reflector (act 112). Relative translation betweenthe scanner and the first assembly, between the first assembly and thesecond assembly, and between the second assembly and the base assemblyis used to accommodate three-dimensional relative translation betweenthe scanner and the base assembly (act 114).

FIG. 4 is a simplified block diagram of additional aspects and/oroptional acts that can be accomplished as part of the method 100. Forexample, the method 100 can include using the base assembly to support athird reflector (e.g., third reflector 70) configured to reflect theelectromagnetic radiation beam to propagate parallel to the thirddirection and to be incident on the second reflector (act 116). Themethod 100 can include operating the scanner to scan the electromagneticradiation beam in at least two dimensions (act 118). The method 100 caninclude focusing the electromagnetic radiation beam to a focal point(act 120). The method 100 can include operating the scanner to scan thefocal point in three dimensions (act 122). The method 100 can includeusing a counter-balance mechanism to inhibit gravity-induced movement ofthe scanner and/or to inhibit transfer of gravity-induced force to aneye coupled with the scanner (act 124). The method 100 can includemonitoring a relative position of at least one of the group consistingof (1) between the scanner and the first support assembly, (2) betweenthe first support assembly and the second support assembly, and (3)between the second support assembly and the base assembly (act 126). Themethod 100 can include inhibiting relative movement during positioningof the scanner relative to the patient between at least one of (1) thescanner and the first support assembly, (2) the first support assemblyand the second support assembly, and (3) the second support assembly andthe base assembly (act 128).

FIG. 5 schematically illustrates relative movements that can be used inthe free-floating mechanism 14 that can be used to accommodate patientmovement, in accordance with many embodiments. The free-floatingmechanism 14 includes the first reflector 66, the second reflector 68,and the third reflector 70. In many embodiments, the free-floatingmechanism 14 includes a linkage assembly (not shown) that is configuredto permit certain relative movement between the scanning assembly 16 andthe first reflector 66, between the first reflector 66 and the secondreflector 68, and between the second reflector 68 and the thirdreflector 70 so as to consistently direct the electromagnetic radiationbeam 26 to the scanning assembly 16 while accommodatingthree-dimensional relative movement between the patient interface device20 and the laser assembly used to generate the electromagnetic radiationbeam 26. For example, similar to the embodiment of the free-floatingmechanism 14 illustrated in FIG. 2, a free-floating mechanism 14 can beconfigured such that the scanning assembly 16 is supported by a firstsupport assembly such that the scanner is free to translate relative tothe first support assembly parallel to the first direction 46, therebymaintaining the location and orientation of the beam 26 between thefirst reflector 66 and the scanning assembly 16. Likewise, the firstsupport assembly can be supported by a second support assembly such thatthe first support assembly is free to translate relative to the secondsupport assembly parallel to a second direction 62, thereby maintainingthe location and orientation of the beam 26 between the second reflector68 and the first reflector 66. And the second support assembly can besupported by a base assembly such that the second support assembly isfree to translate relative to the base assembly parallel to a thirddirection 64, thereby maintaining the location and orientation of thebeam 26 between the third reflector 70 and the second reflector 68.

The free-floating mechanism 14 can also employ one or more relativerotations so as to maintain the location and orientation of pathsegments of the beam 26. For example, the scanning assembly 16 can besupported by a first support assembly such that the scanner is free toundergo a rotation 78 relative to the first support assembly about anaxis coincident with the path segment of the beam 26 between the firstreflector 66 and the scanning assembly 16, thereby maintaining thelocation and orientation of the beam 26 between the first reflector 66and the scanning assembly 16. Likewise, the first support assembly canbe supported by a second support assembly such that the first supportassembly is free to undergo a rotation 80 relative to the second supportassembly about an axis coincident with the path segment of the beam 26between the second reflector 68 and the first reflector 66, therebymaintaining the location and orientation of the beam 26 between thesecond reflector 68 and the first reflector 66. And the second supportassembly can be supported by a base assembly such that the secondsupport assembly is free to undergo a rotation 82 relative to the baseassembly about an axis coincident with the path segment of the beam 26between the third reflector 70 and the second reflector 68, therebymaintaining the location and orientation of the beam 26 between thethird reflector 70 and the second reflector 68.

The free-floating mechanism 14 can also employ any suitable combinationof relative translations and relative rotations so as to maintain thelocation and orientation of path segments of the beam 26. For example,with respect to the configuration illustrated in FIG. 5, thefree-floating mechanism 14 can employ relative translation parallel tothe second direction 62, relative translation parallel to the thirddirection 64, and relative rotation 82, thereby allowingthree-dimensional movement of the patient interface 20 relative to thelaser assembly used to generate the electromagnetic radiation beam 26,and thereby accommodating patient movement.

FIG. 6A is a simplified block diagram of acts of a method 200, inaccordance with many embodiments, of accommodating patient movement in alaser surgery system. Any suitable device, assembly, and/or systemdescribed herein can be used to practice the method 200. The method 200includes using a first support assembly to support a scanner so as toaccommodate relative movement between the scanner and the first supportassembly so as to accommodate patient movement. The scanner is operableto controllably scan an electromagnetic radiation beam and configured tobe coupled with a patient so that the scanner moves in conjunction withmovement of the patient (act 202). The method 200 includes using a beamsource to generate the electromagnetic radiation beam (act 204). Themethod 200 includes propagating the electromagnetic radiation beam fromthe beam source to the scanner along an optical path having an opticalpath length that changes in response to patient movement (act 206).

FIG. 6B is a simplified block diagram of additional aspects and/oroptional acts that can be accomplished as part of the method 200. Forexample, the method 200 can include using a second support assembly tosupport the first support assembly so as to accommodate relativemovement between the first support assembly and the second supportassembly so as to accommodate patient movement (act 208). The method 200can include using the first support assembly to support a firstreflector configured to reflect the electromagnetic radiation beam so asto propagate to the scanner along a portion of the optical path (act210). The method 200 can include using a base assembly to support thesecond support assembly so as to accommodate relative movement betweenthe second support assembly and the base assembly so as to accommodatepatient movement (act 212). The method 200 can include using the secondsupport assembly to support a second reflector configured to reflect theelectromagnetic radiation beam to propagate along a portion of theoptical path so as to be incident on the first reflector (act 214). Themethod 200 can include using the base assembly to support a thirdreflector configured to reflect the electromagnetic radiation beam topropagate along a portion of the optical path so as to be incident onthe second reflector (act 216). The method 200 can include monitoring atleast one of a relative position and a relative orientation of at leastone of the group consisting of (1) between the scanner and the firstsupport assembly, (2) between the first support assembly and the secondsupport assembly, and (3) between the second support assembly and thebase assembly (act 218). The method 200 can include inhibiting relativemovement during positioning of the scanner relative to the patientbetween at least one of (1) the scanner and the first support assembly,(2) the first support assembly and the second support assembly, and (3)the second support assembly and the base assembly (act 220).

FIG. 7 schematically illustrates a laser surgery system 300, inaccordance with many embodiments. The laser surgery system 300 includesthe laser assembly 12, the free-floating mechanism 14, the scanningassembly 16, the objective lens assembly 18, the patient interface 20,communication paths 302, control electronics 304, controlpanel/graphical user interface (GUI) 306, and user interface devices308. The control electronics 304 includes processor 310, which includesmemory 312. The patient interface 20 is configured to interface with apatient 22. The control electronics 304 is operatively coupled via thecommunication paths 302 with the laser assembly 12, the free-floatingmechanism 14, the scanning assembly 16, the control panel/GUI 306, andthe user interface devices 308.

The free-floating mechanism 14 can be configured as illustrated in FIG.2 to include, for example, the first reflector 66, the second reflector68, and the third reflector 70. Accordingly, the free-floating mechanism14 can be configured to accommodate movement of the patient 22 relativeto the laser assembly 12 in any direction resulting from any combinationof three orthogonal unit directions.

The scanning assembly 16 includes a z-scan device 314 and an xy-scandevice 316. The laser surgery system 300 is configured to focus theelectromagnetic radiation beam 26 to a focal point that is scanned inthree dimensions. The z-scan device 314 is operable to vary the locationof the focal point in the direction of propagation of the beam 26. Thexy-scan device 316 is operable to scan the location of the focal pointin two dimensions transverse to the direction of propagation of the beam26. Accordingly, the combination of the z-scan device 314 and thexy-scan device 316 can be operated to controllably scan the focal pointof the beam in three dimensions, including within a tissue of thepatient 22 such as within an eye tissue of the patient 22. As describedabove with respect to free floating assembly 16, the scanning assembly16 is supported by the free-floating mechanism 14, which accommodatespatient movement induced movement of the scanning device relative to thelaser assembly 12 in three dimensions.

The patient interface 20 is coupled to the patient 22 such that thepatient interface 20, the objective lens 18, and the scanning assembly16 move in conjunction with the patient 22. For example, in manyembodiments, the patient interface 20 employs a suction ring that isvacuum attached to an eye of the patient 20. The suction ring can becoupled with the patient interface 20, for example, using vacuum tosecure the suction ring to the patient interface 20.

The control electronics 304 controls the operation of and/or can receiveinput from the laser assembly 12, the free-floating assembly 14, thescanning assembly 16, the patient interface 20, the control panel/GUI306, and the user interface devices 308 via the communication paths 302.The communication paths 302 can be implemented in any suitableconfiguration, including any suitable shared or dedicated communicationpaths between the control electronics 304 and the respective systemcomponents.

The control electronics 304 can include any suitable components, such asone or more processor, one or more field-programmable gate array (FPGA),and one or more memory storage devices. In many embodiments, the controlelectronics 304 controls the control panel/GUI 306 to provide forpre-procedure planning according to user specified treatment parametersas well as to provide user control over the laser eye surgery procedure.

The control electronics 304 can include a processor/controller 310 thatis used to perform calculations related to system operation and providecontrol signals to the various system elements. A computer readablemedium 312 is coupled to the processor 310 in order to store data usedby the processor and other system elements. The processor 310 interactswith the other components of the system as described more fullythroughout the present specification. In an embodiment, the memory 312can include a look up table that can be utilized to control one or morecomponents of the laser system surgery system 300.

The processor 310 can be a general purpose microprocessor configured toexecute instructions and data, such as a Pentium processor manufacturedby the Intel Corporation of Santa Clara, Calif. It can also be anApplication Specific Integrated Circuit (ASIC) that embodies at leastpart of the instructions for performing the method in accordance withthe embodiments of the present disclosure in software, firmware and/orhardware. As an example, such processors include dedicated circuitry,ASICs, combinatorial logic, other programmable processors, combinationsthereof, and the like.

The memory 312 can be local or distributed as appropriate to theparticular application. Memory 312 can include a number of memoriesincluding a main random access memory (RAM) for storage of instructionsand data during program execution and a read only memory (ROM) in whichfixed instructions are stored. Thus, the memory 312 provides persistent(non-volatile) storage for program and data files, and may include ahard disk drive, flash memory, a floppy disk drive along with associatedremovable media, a Compact Disk Read Only Memory (CD-ROM) drive, anoptical drive, removable media cartridges, and other like storage media.

The user interface devices 308 can include any suitable user inputdevice suitable to provide user input to the control electronics 304.For example, the user interface devices 308 can include devices such as,for example, a touch-screen display/input device, a keyboard, afootswitch, a keypad, a patient interface radio frequency identification(RFID) reader, an emergency stop button, and a key switch.

Any suitable laser surgery system can be suitably modified to employ anelectromagnetic beam scanner that is supported by a free-floatingmechanism as disclosed herein. For example, co-pending U.S. provisionalpatent application Ser. No. 14/069,042 filed Oct. 31, 2013 (published asU.S. Publication No. US 2014-0163534 A1), describes a laser eye surgerysystem that includes beam scanning components that form part of a sharedoptical assembly used to scan a treatment beam, an optical coherencetomography (OCT) measurement beam, and an alignment beam. Using theapproaches described herein, such beam scanning components can besupported from a free-floating mechanism so as to accommodate patientmovement as described herein.

FIG. 8 is a schematic diagram of a laser surgery system, in accordancewith many embodiments, in which an eye interface device is coupled to alaser assembly by way of a scanner and free-floating mechanism thatsupports the scanner. The mechanism shown in FIG. 8 could be used inlieu of the assembly shown in FIG. 2, for example working in conjunctionwith the laser assembly 12 from FIG. 1. Thus, FIG. 8 shows an assembly400 example embodiment of a suitable combination of a linkage thataccommodates relative movement between the scanning assembly 16 and thelaser assembly 12 and optical components suitably tied to the linkage soas to form the variable optical path 28 (from FIG. 1). Suchfree-floating head mechanism could be used to move in unison with themovement of a patient.

FIG. 8 shows another example free-floating head mechanism assembly 400with three degrees of freedom of movement about three axes x, y and z.Thus, the system includes a base assembly 410 upon which components areattached. The base assembly is stable relative to a floating scanningassembly 440 and objective lens assembly 420 which are attached to thebase assembly 410 but are able to move in three degrees of freedomaccording to the embodiments described here.

The base assembly 410 is shown as a framework of parts that are arrangedto support the components of the system here. The base assembly 410could be made of any number of things including metal such as aluminumor steel, it could be made of plastics or composites, or a combinationof things. The example base assembly 410 in FIG. 8 generally has twoflat platforms 412 that are held apart by various struts 414. Theexample is not intended to be limiting and any arrangement of supportstructure could be used.

Regarding the relative motion of the floating scanning assembly 440 andobjective lens assembly 420 relative to the base assembly 410, the firstaxis of movement is a z axis which is made possible using a z axisspring mechanism 430 and vertical z axis bearings 432. The z axisbearings 432 allow the floating scanning assembly 440 and objective lensassembly 420 to move vertically, up and down, relative to the baseassembly 410.

Such a bearing system may include rollers and a linear track or railsystem that keeps the floating scanning assembly 440 and objective lensassembly 420 from shifting off of a smooth and direct movement in anyparticular axis. In such an assembly, a roller, or multiple rollers areconfigured to contact a track or rail. Each of the two, the rollerassembly and track, are attached to either the base assembly or thefloating scanning assembly 440 and lens assembly 440. Thus, as therollers and track interact, the floating scanning assembly 440 and lensassembly 440 movement, relative to the base assembly 410 is forced intoa linear direction, according to the orientation of the bearing track,in this example, that is along the z axis. As discussed herein, acombination of such bearings, can allow for the floating scanningassembly 440 and lens assembly 440 to move about more than one axis andmore than one degree of freedom, relative to the base assembly 410,depending on how many axes are configured.

It should be noted that the example of these roller and track bearingsin FIG. 8 is merely exemplary and any kind of bearings could be used.

To complement the vertical bearings 432 in the example embodiment shownin FIG. 8, a system of springs 430 are shown that help keep any verticalmovement of the floating scanning assembly 440 and objective lensassembly 420 from happening unless acted upon by a force other thangravity, such as a user or operator positioning the floating scanningassembly 440 and objective lens assembly 420. In FIG. 8, the examplemechanism shown includes two z axis springs 430 but it should be notedthat any arrangement of multiple or one spring could be used. Thesesprings 430 can counteract the force of gravity, which accelerates thefloating scanning assembly 440 and objective lens assembly 420 towardthe earth. Thus, the z axis is the only axis that needs additionalassistance to counteract gravity, hence the springs.

In the example embodiment in FIG. 8, the z axis springs 430 are shown asmetal tapes wound around spring loaded bearing spools. When the floatingscanning assembly 440 and objective lens assembly 420 is moved by anoutside force such as a user or operator in the vertical dimension, or zaxis, the metal tapes coil or uncoil respectively and the spring tensionwithin the coils keep the floating scanning assembly 440 and objectivelens assembly 420 from free falling due to gravity. It should be notedthat the wound tape spring example is not intended to be limiting. Anykind of spring mechanism or other mechanism could be used with similareffect. For example, a hydraulic piston system could be used tocounteract gravity, a coiled wire spring system could be used, a pulleysystem could be used, a geared system could be used, a magnetic systemcould be used, etc. Additionally a locking mechanism could be used tohold the floating scanning assembly 440 and objective lens assembly 420in place, relative to the base assembly, after it is positioned.

The free-floating head mechanism 400 also includes bearings in thehorizontal x axis 434 and the horizontal y axis 436 as well as the zaxis as discussed. Such x axis and y axis bearings keep the floatingscanning assembly 440 and objective lens assembly 420 from slipping orshifting, relative to the base assembly 410, in the x and y axisdirections. Used in combination, these bearings allow for the floatingscanning assembly 440 and objective lens assembly 420 to move in ahorizontal plane, for example.

It should be noted that the horizontal bearings do not necessarilyinclude springs such as those used for the z axis because generallythere is not a force acting upon the horizontal plane as there is in thevertical plane with gravity. But the bearings in any degree of freedomcould include a brake or lock mechanism to keep the floating scanningassembly 440 and objective lens assembly 420 locked into a certainposition, for any or all of the three axes. Such a brake could be a pinand hole, either spring loaded or not. A lock could be a gear mechanismwith a latch that holds the gear. A lock could be a stopper on a springor piston as well. It could be a solenoid brake, either manuallyoperated or magnetically. Any of various locks could be used in any oneor combination of the axes.

The combination of the three axis bearing arrangement as shown in FIG. 8allows for the entire floating scanning assembly 440 and objective lensassembly 420 to be moved, by an operator or user, relative to the baseassembly 410 in any position of the three axes: up and down, left andright, and in and out, and thus any position in three dimensional space,within the boundaries of the bearing tracks. Thus, the range of motionis only limited by the physical length of the bearing rails or tracks ineach direction. If the z axis bearing rail or track has a total lengthof 12 inches, the range of motion of the floating scanning assembly 440and objective lens assembly 420 relative to the base assembly 410 wouldbe 12 inches. The x axis bearing could have the same length or differentlength. The y axis bearing could have the same length or differentlength. The combination of the three axis bearings would define therange of motion within the three degrees of freedom for the floatingscanning assembly 440 and objective lens assembly 420. In combination,these three axes allow for the floating scanning assembly 440 andobjective lens assembly 420 to be positioned in any three dimensionalcoordinate within the range of the system.

Referring now to FIG. 9, the free-floating head mechanism 400 isdepicted with the three axes of movement for the floating scanningassembly 440 and objective lens assembly 420 relative to the baseassembly 410 from FIG. 8, as shown with arrows. The vertical z axis 462,the horizontal y axis 466 and the horizontal x axis 464 are all shownwhich are the three axes in this example that the floating scanningassembly 440 and objective lens assembly 420 are able to move relativeto the base assembly 410 from FIG. 8.

It should be noted that the combination of the three axis system asdescribed here is merely exemplary. Fewer axes could be used, oradditional axes could be used. In certain example embodiments,additional axes of rotations could be added for example, with a rotatingor pivoting bearing assembly or assemblies attached to the base assembly410 as well. Such an embodiment is not shown, but could be configured toadd one, two, or three more degrees of freedom to the movement of theassembly 400.

Certain example embodiments may include motors, attached to or incommunication with the bearings. Such motors could actuate movement ofthe optical scanning module 440 and lens assembly 420 relative to thebase assembly 410. Such motors could be configured to allow the movementof the assembly in a remote fashion, using wired or wirelesstransmitters. Example embodiments include motors that could be directedby a program that receives feedback regarding patient input, and directsthe assembly to move to counteract such patient movement. It should benoted that the operation of such motors could be via a remote controldevice or local operation. Wireless or wired control could be utilizedto move the system. Wireless control could be via WiFi or cellular orBluetooth Low Energy systems, or any number of other communicationmechanisms.

Referring again to FIG. 8, as the overall system is designed to directbeams of energy, as shown in FIG. 1, to its intended target, through thefloating scanning assembly 440 and the lens portion 420. Any movement ofthe floating scanning assembly 440 and objective lens assembly 420relative to the base assembly and potentially the source of the beammust be compensated for. An arrangement of mirrors can be used, incertain example embodiments, to direct such an energy beam into thefloating scanning assembly 440 and objective lens assembly 420 no matterwhere in the floating scanning assembly 440 and objective lens assembly420 are, relative to the base assembly 410. Thus, the mirrors could bearranged to move to keep the beam directed into the floating scanningassembly 440 and objective lens assembly 420 or be fixed to the variousportions of the base assembly 410 in order to maintain the beamdirection into the floating scanning assembly 440 and objective lensassembly 420. Such a beam source, such as a laser, could be mounted tothe base assembly or some other structure attached to or nearby the baseassembly. Any kind of system could be used, as described in U.S.application Ser. No. 14/191,095 Laser Eye Surgery Systems or other suchsystems.

The horizontal y axis fixed mirror 450 works in conjunction with thehorizontal y axis floating mirror and x axis fixed mirror 452. Finally,the horizontal x axis floating mirror, and the vertical z axis fixedmirror 454 direct the beam into the floating scanning assembly 440 andlens portion 420. These mirrors keep the energy beam aimed at thefloating scanning assembly 440 and lens assembly 420, no matter wherethe floating scanning assembly 440 and objective lens assembly 420 ismoved on its three axis bearing system, relative to the base assembly410.

It should also be noted that the bearings, springs and mirrors are shownin representative places on the base assembly 410 of the assembly. Thesecomponents could be moved to other parts of the base assembly 410,oriented in different ways than are shown in the example of FIG. 8.Additional mirrors could be used, for example in embodiments with morethan three degrees of freedom.

In certain example embodiments, a patient support structure, such as forexample a bed or gurney support, could be coupled to the base assembly410 or base assembly support structure and be used to accommodate forpatient movement relative to the system such as that discussed in FIGS.3, 4, 5 and 6A. An arrangement of motors in communication with acomputer that can sense patient movement, provide a feedback loop andmove the patient support structure accordingly, to compensate and keepthe patient in place of the energy beam coming through the floatingscanning assembly 440 and objective lens assembly 420. Such a patientsupport structure could also be moved manually or through direction of auser into such motors.

Conclusion

Other variations are within the spirit of the present invention. Thus,while the invention is susceptible to various modifications andalternative constructions, certain illustrated embodiments thereof areshown in the drawings and have been described above in detail. It shouldbe understood, however, that there is no intention to limit theinvention to the specific form or forms disclosed, but on the contrary,the intention is to cover all modifications, alternative constructions,and equivalents falling within the spirit and scope of the invention, asdefined in the appended claims.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. The term “connected” is to beconstrued as partly or wholly contained within, attached to, or joinedtogether, even if there is something intervening. Recitation of rangesof values herein are merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range,unless otherwise indicated herein, and each separate value isincorporated into the specification as if it were individually recitedherein. All methods described herein can be performed in any suitableorder unless otherwise indicated herein or otherwise clearlycontradicted by context. The use of any and all examples, or exemplarylanguage (e.g., “such as”) provided herein, is intended merely to betterilluminate embodiments of the invention and does not pose a limitationon the scope of the invention unless otherwise claimed. No language inthe specification should be construed as indicating any non-claimedelement as essential to the practice of the invention.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

The foregoing description, for purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Many modificationsand variations are possible in view of the above teachings. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, to therebyenable others skilled in the art to best utilize the invention andvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A system to support a laser eye surgery device,comprising: a beam source configured to generate a laser beam to performthe laser eye surgery; an optical scanning assembly including scanningelements configured to scan a focal point of the laser beam in at leasttwo dimensions to different locations within the eye, wherein theoptical scanning assembly is coupled to a patient interface device forcontacting the eye and includes a microelectromechanical force sensorconfigured to measure a force on the eye by the patient interfacedevice, the microelectromechanical force sensor being configured toconvert an applied force into an electrical signal with a response timeof tens of microseconds, the microelectromechanical force sensor beingpreloaded in a compression state, wherein the optical scanning assemblyand the patient interface device are configured to freely follow amovement of the patient's eye relative to the beam source in x, y and zdirections so that an optical path between the beam source and theoptical scanning assembly is variable; a sensor to receive a portion ofthe laser beam which has been reflected from the focal point back alongthe variable optical path, and generate an intensity signal indicativeof the intensity of a portion of the laser beam; a base assembly; amechanical structure for mounting the optical scanning assembly to thebase assembly, including: a horizontal x axis linear bearing configuredto support a translation movement of the optical scanning assemblyincluding all its scanning elements relative to the base assembly onlyin the x axis direction; a horizontal y axis linear bearing, mounted onthe base assembly, configured to support a translation movement of theoptical scanning assembly including all its scanning elements relativeto the base assembly only in the y axis direction; a vertical z axislinear bearing, mounted on the base assembly, configured to support atranslation movement of the optical scanning assembly including all itsscanning elements relative to the base assembly only in the z axisdirection; a vertical z axis spring, configured to counteract the forcesof gravity on the optical scanning assembly in the z axis direction; atleast two mirrors of the variable optical path mounted on the mechanicalstructure and configured to translate relative to each other to reflectthe laser beam from the beam source into the optical scanning assemblyno matter where the optical scanning assembly is located on the x axisbearing, the y axis bearing and the z axis bearing; and a plurality ofmotors, attached to the bearings and configured to actuate movement ofthe optical scanning assembly in the x, y and z axes relative to thebase assembly, the plurality of motors being controlled to move theoptical scanning assembly in response to feedback signals from themicroelectromechanical force sensor.
 2. The system of claim 1 whereineach of the linear bearings is a roller and rail bearing and thevertical z axis spring is a pair of coiled metal tapes each coiledaround a spring loaded spool.
 3. The system of claim 1 wherein theoptical scanning assembly includes a confocal lens assembly.
 4. Thesystem of claim 1, further comprising: a patient support structure,configured to support the base assembly and accommodate relativemovement between the base assembly and patient support structure.
 5. Thesystem of claim 1 wherein the at least two mirrors include a firstmirror supported by the horizontal x axis linear bearing to move in thex axis direction and configured to reflect the laser beam from the xaxis direction to the y axis direction, and a second mirror supported bythe horizontal y axis linear bearing to move in the y axis direction andconfigured to received the laser beam from the first mirror and reflectthe laser beam from the y axis direction to the z axis direction.